In areas which experience earthquakes, a very high percentage of the number of fires which are caused by the quake are the result of gas-heated, hot water tanks which tip over during the earthquake. It has been estimated that as high as 90% of the house fires which occur are a direct result of water heater instability.
Typically, water heaters are either not stabilized at all (other than by their plumbing), or they are mounted by plumber's strapping or L-shaped brackets to sheetrock, or occasionally framing studs, by a nail or screw. Moreover, the hot water tank is often placed on a pedestal or raised section of the flooring where such placement further increases the water heater's instability and susceptibility to tipping. Little in the way of code requirement for the securement of hot water tanks has been enacted. While plumber's strapping of L-shaped brackets have been adequate mounting devices during stable, nonearth movement conditions, various problems have occurred when such devices were exposed to the severe acceleration caused by a earthquake. Earthquakes often generate P-waves (rolling type compression waves) which travel along the surface of the earth's crust. These waves tend to sway objects from side-to-side and are generally the main cause of most building damage due to the earthquake itself. Likewise, the momentum of the water tank gained due to seismic accelerations, coupled with the fact that a filled 50 gallon hot water tank can weigh in excess of 500 pounds, has led to disastrous results. Under earthquake conditions, strapping frequently will go slack or experience a stress reversal which allows the water tank transverse or lateral momentum to build, and the increasing momentum pulls the nail or screw from the wallboard or breaks the strapping or brackets. Since brackets are often secured to the thin metal of the tank housing by screws, such fasteners also can pull out of the tank wall. Thus, as the acceleration becomes significant, prior water tank securement assemblies have typically failed under earthquake conditions. As already mentioned, this instability of gas-heated water tanks has resulted in fires and major gas leaks.
Few, if any, attempts to lessen or overcome the problem of gas-heated, hot water tank instability have been made. The prior art has not addressed the peculiar environment inherent in an earthquake condition, nor has the prior art addressed the problem of the extreme mass of a hot water tank. What attempts have occurred have largely been based upon providing a separate enclosure for the water storing tank. Thus, Arzberger, U.S. Pat. No. 3,730,144, for example, discloses a hot beverage dispenser enclosed in a housing. The storage tank is secured via a bracket and a strapping means which is subsequently connected by a vertical stabilizing rod embedded in the base of the water tank. More importantly, Arzberger does not fasten the water tank to the housing nor does the bracket employed provide a versatile alignment means capable of securement to the varying locations at which framing studs may occur in a wall. Thus, the simplistic bracket and strapping means utilized in Arzberger is not adequate for the specific requirements of the present invention.
There are other means for mounting tanks within enclosures in which straps and buckles are employed to secure the tank. One such securement means is disclosed in U.S. Pat. No. 3,805,988 to Walker et al. However, the assembly set forth is not suitable for mounting the type of heated water tanks used in homes and industries. The mounting means utilized in Walker is only sufficient for smaller portable tanks which are periodically removed and replaced. Walker does not have the versatility of aligning the means for attachment to the enclosure with the framing studs as required by the present invention. Furthermore, the strapping and buckle means supplied in Walker are more adequate for ease of removal. Thus, it follows that because of the inappropriate design and the excessive weight of a hot water tank, it would eventually pull free of the sheetrock under earthquake conditions.
Finally, there are other securing methods which relate generally to strapping assemblies for hanging pipes. Typical of these systems are the pipe mountings disclosed in Loosdon and Norton, U.S. Pat. Nos. 4,768,741 and 4,844,396, respectively. Both the strapping assemblies, however, are not suitable for use with large water storage tanks under earthquake type conditions.
While the prior disclosures have been satisfactory for many applications, it has been found to be highly desirable to provide an assembly capable of securing a hot water tank of substantial mass to a stable structure, such as the framing studs of a building.
Accordingly, it is an object of the present invention to provide a hot water tank bracket assembly which can withstand the substantial seismic accelerations common to moderated or large earthquakes.
It is another object of the present invention to provide a hot water tank bracket assembly which provides a bracket suitable for placement juxtaposed a wall which simultaneously cradles the water tank for maximum stability, yet facilitates the removal and replacement of the water tank.
It is yet another object of the present invention to provide a hot water tank bracket assembly which can be retrofit in existing installations for positive fastening of the tank to framing studs of a building.
It is a further object of the present invention to provide a hot water tank bracket assembly which is durable, compact, easy to maintain, has a minimum number of components and is economical to manufacture.
The apparatus of the present invention has other objects and features of advantage which will become apparent from and are set forth in more detail in the description of the Best Mode of Carrying Out the Invention and the accompanying drawing.